Leather-sewing machine with curved oscillating needle



April 8, 1953 1; 1,489,286

7 L. STREIBEL LEATHER SEWING MACHINE WITH CURVE'D OSCILLATING NEEDLE Filed Jan. 13 1923 Fig.1.

Inventor:

Patented Apr. 8, 1924,

UNITED STATES PATENT OFFICE.

LUDWIG STREIBEL, or KARLSRUHE, GERMANY, AssIenoR or ONE-HALF To ADAM EHRESMANN, 0F KARLSRUHE, GER-MANY. 1

LEATHER-SEWING MACHINE WITH CURVED OSCILLATIN'G NEEDLE.

Application filed January 13, 1923. Serial No. 612,869.

To all whom it may concern:

Be it known that I, LUDWIG STREIBEL, a German citizen, residing at Karlsruhe, Germany, have invented certain new and useful Improvements in Leather-Sewing Machines with Curved Oscillating Needles (for which I have filed an application in Germany August 26, 1921), of which the following is a specification. l I

My invention relates to leather sewing machines, more especially sole lining machines, that make use of'a circularly curved needle oscillating in the direction of the curve, and my invention has for its object to provide a presser foot which, while the needle is in operation, bears firmly upon the work and thus holds it securely without any risk of movement. The novel feature of this presser foot is a spiral cam path, which before the needle begins its "operation is allowed to rotate under the action of a spring, so that by means ofalever, provided with a roller running in the space between the coils of the spiral cam path, the presser foot is applied to the work with uniform pressure, irrespective of the thickness thereof, and which spiral cam path, when the operation of the needle is completed, is reverselyrotated by a gear operated by the driving-shaft, so that it lifts the presser foot from the workbymeans of said lever.

A constructional example of the subject matter of my invention is illustrated in the accompanying drawing in which Figs. 1 and 3 shew the parts of a sole lining machine provided with a pressure foot according to the invention in side elevation and in plan, and Fig. 2 is a portion of Fig. 1 with certain parts of the machine in a different position.

The needle a is clamped in the needle holder b which is mounted loosely on the shaft 0 and is oscillated by the driving shaft d by means of the crank e and the connecting rod 7. On each side of the needle holder 6 is likewise mounted loosely on the shaft 0 an arm 9. These two arms are rigidly connected to each other by a guide plate h which, like the needle (1, is curved circularly and concentrically with the shaft 0, and by a plate a, which is attached at an angle to the lower end of the guide plate h. The latter has in it a longitudinal slot for the passage of the sewing thread and in its inner side a longitudinal groove, in which the needle a slides to and fro, and thus forms the needle guide.

a 'hole in it for the passage of the needlea and forms withthe arms 9 the presser foot proper. I I

To the hub of the front arm '9 is rigidly connected a lever Z, which carries on its free end a roller m. In front of this lever is mounted a circular disc n, which is adapted to rotate on a horizontal pino and carries at the back a rigid spiral cam path 37,

pin 0. To the front ofthe hub r is secureda crank handle t, and in it is mounted a helical spring u, which is attached by one end to the flange of the sleeve .9 and by the other'end to the ratchet wheel 9 andthus tends to rotate the parts 02, p, q, r and t in" a counter-clockwise direction. In the ratchet wheel 9 is engaged'by a -spring 1) one pawl shaped end of aratche't bar w which is guided at the middle on a pin w fixed in the frame of. the machine and at the other loop shaped end on 'the'dri'ving' shaft d. To' this end of the bar w is secured a'tooth 'y,which projects into the path of a cam z fixed on the front of the crank e.

When the driving shaft 0? rotates (in a clockwise direction) the ratchet bar w is alternately pushed to the right by the cam 2, which slides over the tooth y, and drawn back to the left by the spring 11. When it moves towards'the right it first sets the ratchet wheel 9 with the disc n and the spiral'cam path p in rotation in a clockwise direction, the spiral cam path ;0 lifting the presser foot gi from the work lying on the stitch plate 71:, by means of the lever Z. On continuing to move to the right the bar w is raised by the guide pin a: in consequence of the oblique position of the guide slot and thus brought out of engagement with the ratchet wheel In consequence, this latter together with the disc n and the spiral cam path 32 is rotated in a counterclockwise direction by the spring a, the

The plate has, like the stitch plate-k which lies beneath it,

spiral cam path again pressing the presser foot 9-41 down upon the work, by means of the lever Z. On moving towards the left the left hand end; of the ratchet bar w slides idly over theteeth of the ratchet wheel g.

The movement of the ratchet bar w towards the right only commences after that of the connecting rod f has already taken place to half its extent, and consequently the lifting of the presser foot from the .work only takes place after the needle a has emerged therefrom. The spiral cam path p presses the presser foot down upon the work with a uniform pressure irrespective of the thickness'thereof and therefore holds it securely in every position so that it cannot yield to the strongest pressure. By means of the crank t the 'disc n together with the spiral cam path p can be rotated and thereby the presser foot g-z' raised or. lowered at will and at any time.

What I claim as my invention and desire to secure by Letters'Patent is 1. In a leather sewing machine in combination, a driving shaft, a second shaft, a needle holder, a needle clamped in said needleliolder, a presser foot, a needle guide rigidly connectedtofsa'id presser foot, said needle and said needle guide being curved circularly and concentrically with said second shaft, said 'needle holder and said presser foot with said needle guide being oscillatorily mounted on said second shaft, means for oscillating said needle holder by said driving shaft, a pin, a rigid spiral cam path rotatably mounted on said pin, a lever rigidly connected to said presser foot and also oscillatorily mountedon said second shaft, a roller carried by said lever and engaging between the coils of said spiral cam path, a spring tendingto rotate said spiral cam path in one direction so as to press said presser foot down by means of said lever, means for intermittently rotating said spiral cam path by said driving shaft in the other directionso as to lift said presser foot, and means for rotating said spiral cam path by hand.

2. In a leather sewing machine in combination, a drivingshaft, a second shaft, a needle holder, a needle clamped in said needle holder, a presser foot, a needle guide rigidly connected to said presser foot, said needle and said needle guide being curved circularly and concentrically with said second shaft, said needle holder and said presser foot with said needle guide being oscillatorily mounted on said second shaft, a crank provided on said driving shaft, a rod connecting said crank to said needle holder so as to oscillatesaid holder on rotation of said driving shaft, a pin, a rigid spiral cam path rotatably mounted on said pin, a lever rigidly connected to said presser foot and also oscillatorily mounted'on said second shaft, a roller carried by said lever and engaging between the coils of said spiral cam'path, a spring tending to rotate said spiral cam path in one direction so as to press said presser foot down by means of said lever, a fixed second pin, a ratchet bar having a'pawl shaped-end and a loop shaped endand being guided at the latter on said driving shaft and in a position betweenboth ends on said second pin, a ratchet wheel rigidly connected to said spiral cam path, a second spring tending to engage said pawl shaped end in said ratchet wheel and to move said ratchet bar in one direction, means for moving said ratchet bar by said crank and thereby rotating said ratchet wheel together with said spiral cam path in the other direction so as to lift said presser foot, and means for rotating said spiral cam path by hand.

In testimony whereof I aflix my signature.

UDWIG STREIBEL. [L.S.]

In the presence ofj MAURICE W. ALTAFFER, [n s.] ERIC W. Srrrz. [n s.]- 

